Such a device is known from German published specification No. 3501288 (U.S Pat. No. 4,691,559, English specification No. 8503109, Japanese patent application No. 87647/85).
As emerges from the German published specification, page 31, para. 1, last sentence, it is necessary to fit the test body in a "completely impact-free" manner.
The device described therein has the advantage that for the first time in the field of hardness measurement of the thinnest surface layers, it is possible to measure micro-hardness. The method of measurement is non-destructive. In the meantime, however, it has been found that the test body must be fitted in an even more impact-free condition than one might previously have imagined in order to obtain from the device everything which the device can offer in terms of surface hardness measurement and micro-hardness measurement.